U.S. Pat. No. 3,774,184 on a "Heat Responsive Cable Assembly" was issued to me on Nov. 20, 1973. It discloses a pair of helically wound wires, each coated with heat sensitive insulation. In the event of a local high temperature condition, the wire insulation is vaporized in response to the high temperature, the two wires come into contact. The crossed wires close a circuit to activate an alarm. The geometry of the helix is also a factor in the thermal response of the device. The disclosure of that patent is incorporated herein by reference.
The heat responsive cable described in my earlier U.S. Pat. No. 3,774,184 was intended for installation by itself, within the walls of a house for example, as a means of fire detection and alarm. As originally contemplated in that earlier patent, my heat responsive cable required its own installation, separate from and independent of the electrical power cables installed within the same walls.
The cable described herein is both an extension and an improvement of my earlier heat responsive cable invention.
It is an object of this invention to provide a safety circuit along the length of a power cable.